Field
The described technology generally relates to an organic light-emitting diode display.
Description of the Related Technology
An organic light-emitting diode (OLED) includes two electrodes and an interposed organic light emitting layer. Electrons injected from one electrode and holes injected from the other electrode are coupled in the organic light emitting layer so as to form exciton and the exciton discharges energy to thereby emit light.
An OLED display includes a matrix of pixels including OLEDs, and each pixel includes a plurality of transistors for driving the OLED and a storage capacitor.
The storage capacitor included in each pixel is written with a data voltage during a data record period. The storage capacitor adjusts a current flowing in a driving transistor by holding the data voltage written during a next light emitting period to thereby allow the OLED to be emitted at a specific gray scale corresponding to the data voltage.
In general, since a light emitting period in which the storage capacitor holds the data voltage is relatively short upon a normal driving, a flicker phenomenon does not occur or is not viewed by a user.
However, since the number of times the data is written is reduced in a low frequency driving for reducing power consumption, the period in which the storage capacitor holds the data voltage is relatively increased.
Therefore, charges stored in the storage capacitor exit through a current leakage path over time, and a value of voltage held in the storage capacitor is dropped. In this case, since a change in luminance of the OLED occurs, the flicker phenomenon can occur.
In addition, if a transistor formed on the current leakage path is irradiated with external light or leakage light of a neighboring pixel, photo-leakage currents flow in the corresponding transistor.
Therefore, even though the corresponding transistor turned off, the charges stored in the storage capacitor exit along the flow of the current, and the flicker phenomenon is intensified.
Therefore, there is a need for a layout of an OLED display that can block external light or leakage light for the transistor formed on the current leakage path.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it can contain information that does not constitute the prior art that is already known in this country to a person of ordinary skill in the art.